Solder



Feb. 21, 1961 R. L. TRIPLETT RING TYPE POLE PIECES AND METHOD OF MAKING Filed Sept. 26, 1958 I 2 Sheets-Sheet 1 INVENTOR.

24 L. T/Q/ ETT BY AffaRNEVfi Feb. 21, 1961 R. L. TRIPLETT RING TYPE POLE PIECES AND METHOD OF MAKING Filed Sept. 26, 1958 2 Sheets-Sheet 2 STEP-2 INVENTOR. PAY L. Te/PLETT BY 7 )f/ A rramvE V5 'nit States. Patent Di RING TYPE POLE PIECES AND IVIETHOD OF MAKING Ray L. Triplett, Bluifton, Ohio, assign'or to The Triplett Electrical Instrument (10., Blulfton, Ohio, a corporation of Ohio Filed Sept. 26, 1958, s61. No. 763,683 Claims. or. 324-151) This; invention relates to electrical instruments and particularly to electrical instruments of the DArsonval type and 'to methods of manufacturing such instruments.

A DArsonval type electrical instrument movement comprises a magnetic frame that includes an air gap in which a coil moves against the bias of a spring so that anindication can be had on a dial by a pointer fixed to the coil of the amount of current passing through the coil. g.

The forming. of the magnetic frame is important be cause the air gap in which the coil moves should be as uniform as possible and the flux distribution along the air gap sohuld be determinable to a high degree, usually being uniformly distributed, and the magnetic frame must have the characteristics of permanence, of configuration and be capable of being strongly magnetized;

At the present time a great many such magnetic frames are constructed of sintered steel which is pressed to the desiredvshape and after assembling a permanent magnet with such, pressed steel components, the magnetic frame is finally shaped as to the critical portions thereof in- 2,972,717 Patented Feb. 21,1961

'ice v Figure. 5 is a perspective view showing a singlelamin tion of the magnetic frame in exploded form, I

Figure. 6 is a plan view showing in detail the arrangement and location of the various parts of the magnetic frame, a V

Figure 7 is a more or less diagrammatic representation of one manner in which the laminations ofthe magnetic frame could be formed,

Figure 8 is a sectional view indicated by line 8-8 on Figure 7 showing the punching out of parts of the laminations,

Figure 9 is a sectional view indicated by line 9--9 on Figure 7 showing a step in the manufacture of the laminations wherein brass slugs are struck into the steel laminations,

Figure 10 is a sectional view indicated by line 10-10. on Figure 7 showing a step wherein the brass slugs are 7 expanded into pressure engagement with the surrounding I final steps in the formation of the laminations,

cluding the pole faces that help define the air gap and A still further object ofthis invention is to provide 7 a magnetic frame structure for a DArsonval type movement in which the various portions, of themagnetic, frame are rigidly fixed relative toeach other at the timed constructing the frame thereby making for an instrument having better characteristics and longer life.

It is, also an object of this invention topprovide a magnetic frame for an electrical instrument anda method of making the frame which permits the use of cheaper materials without sacrificing any of the desirable qualities of the resulting instrument.

These and other objects and advantages will become more apparent upon reference to the accompanying drawing in which:

steel, v

Figures 11 and 12 are sectional views indicated by lines 11-11 and 1212 respectively on Figure 7 showing the Figure 13 is a view diagrammatically illustrating the riveting together of a stack of the laminations to form the body of the magnetic frame, i

Figure 14 illustrates the step of pressure the permanent magnet portion of the frame into posit-ion, I

Figure 15 diagrammatically illustrates the. breaching of the pole faces of the magnetic frame and the notches adjacent the pole faces that receive'the sides of the. in strument movement, and i Figure 16illustrates the dipping of the magnetic frame in molten solder.

Referring to the drawings more in detail, the instrument '10 in Figure 1 comprises, the usual scale 12 over which a pointer 14 sweeps with the pointer beingfastened to a coil that is rotatably mounted in a coil frame so as to make up the instrument movement proper of the instrument and which instrument movement proper is mounted in a permanent magnet frame 16,

'In Figures 2 and 3' it will be noted that the bridge frame 18 is preferably a one piece frame, die cast, for

example, and that pivot screws 20 and 22 in the ends thereof, journal the ends of the pivot shafts that are.

. coil effects connection of the opposite turn of the coil withan arm 30 that is insulated from frame 18. Arm 30.

' and frame 18 are connected with terminals 32 and 34 and electric current is in this manner supplied to moving coil 24. I I

Bridge frame 18 has extending between the opposite sides thereof a pair of bridge members 36 and carried by these bridge members is a core 38 of magnetic material. As will be seen in Figure 3, the coil 24 moves in an air gap defined by core 38, alower pole face 40 of the mag- Figure 1 is a front elevational view of a typical 'elee trical instrument embodying a magnetic frameaccording to this invention, n I

Figure 2 is a sectional view indicated by line 2-2 on Figure. 1 showing the mounting of the movement of the instrument in the magnetic frame,

Figure 3' is a sectional view indicated by line 33 on Figure-2 showing the portion of the magnetic frame in which the moving coil'is mounted,

.l-"1igure 4is a perspective view showing the magnetic frame with theimovement" portion removed theretrem,

netic frame and an upper pole face 42.

netic metallic members 1 0,, One "at each end of pole member 46. Each memb'e'rfStl has 'a tongue 52 extend i'ng into'a notcl 'ini the adjacent endfofpole'member 4'6 tending into the correspondingly shaped notch in the inside of ring 44.

As will be seen in Figures 4 and 5, the magnetic frame 16 is made up of a plurality of individual laminations 56 interconnected by rivets 58. The permanent magnet 48, which is preferably an Alnico such as AlnicoVI, is, of course, a single piece of the same front to back dimensions as the assembled laminations.

The inserted non-magnetic members 50 are held tightly in place by being swaged or extruded outwardly after they are in position between ring 44 and pole member 46 as indicated by the depressed portions 60. a

' According to this invention the laminations are formed in their entirety by punching and pressing operations so that the laminations can be produced rapidly and inexpensively. This also permits the-use of rolled steel which is more inexpensive than sintered steel and is more dense,

thus providing for more permanence of the magnetic I circuit.

It will be seen from Figures 2 through 6 that the pole faces 40 and 42 are separated by notches '62 and which notches receive the sides of the bridge frame 18. The bridge frame is thereby located between the pole faces so that highly accurate assembling of the instrument can be arrived at quite easily. Projections 64 on the sides of frame 18 engage the ends of the magnetic frame and a will result in a finished magnetic frame. The magnet 48 may be stacked in place as indicated by the stack marks 100, if so desired.

The magnetic frame of the present invention exhibits extreme rigidity and excellent magnetic characteristics and is more inexpensive both as to material and labor than previous magnetic frames formed of powdered steel pressed to shape and sintered.

The ring'formed on the outer portion of the magnetic frame is beneficial because of its shielding effect and also contributes to the rigidity of the magnetic frame. The grooves on opposite sides of the core space that receive the bridge frame 18 provide for extremely accurate alignscrew 65 may be'employed to clamp the frame in posiseries of stations with openings 72 being punched out in one station and which openings are for receiving the brass members 50.

In another station the brass members 50 are forced into the openings 72 and in a following station the. members 50 are swaged or extruded into extremely tight relationship with the surrounding steel.

In still another station the strip may have apertures '74, 76 and 7S stamped therein, and in a final station the v ment of the core and coil in the magnetic frame because the alignment does not depend on the surface flatness of conventional bridge parts fitted to the outside surfaces of the magnetic frame structure as is usually done.

It will be understood that this invention is susceptible v to modification in order to adapt it to different usages and conditions and, accordingly, it is desired to comprehend such modifications within this invention as may fall within the scope of the appended claims.

I claim:

1. In an electrical instrument; a ring of magnetic material, means defining a first arcuate pole face on the inside of said ring at one side thereof, a generally barlike member of magnetic material substantially smaller than the space inside the ring located inside the ring and having means defining a second arcuate pole face thereon arranged in opposed relation to the first pole face to define a generally cylindrical region therebetween, non-magnetic metallic elements extending from the ends of said bar-like member to the ring, means rigidly conlaminations 56 may be'blanked out of the strip. The

lamination at this time is completelyform'ed except for the broaching and cleaning up that, is to be done thereon after the frame is assembled.

Figure 8 illustrates diagrammatically the step-of forming aperture 72 and illustrates punch elements 80 striking outthe slugs 82 which are the same shape as the brass members 50.

In Figure 9 a strip "84 of brass is placed on top of the steel strip 70 and using the steel strip as a die, punches 86 strike the brass members from the brass strip and 7 ure 12 a punch 94 strikes the completed lamination 56 out from strip 70.

Thereafter the proper number of laminations are 7 stacked together, in this case eight, and rivets $6 are placed in aperture 78 and riveted over to fix the laminations together to form the body of the magnetic frame.

' At this time the magnet 48 may be pressed in place as indicated in Figure 14 and thereafter a broaching tool 98 may be pressed through the frame to cleanup and accurately size the pole faces of the magnetic frameand thenotches 62. The entire magnetic frame may then be i dipped in molten silver solder, or the like, as indicated in Figure 16, and thereafter a cleanup ofthe pole face'areas necting said elements with both the member and the ring, the connection comprising notch means formed in one thereofiand projection means formed on the other thereof extending into said notch means, a non-magnetic frame in the ring between said pole faces, atcore in the frame concentric with the pole faces, and a coil rotatable in the frame having side portions in the spaces between said core and pole faces, there being a permanent magnet fitted between the inside of the ring and the side of the bar-like member opposite the side with the pole face thereon.

2. In an electrical instrument; a ring of magnetic material, means defining a first, arcuate pole face on the inside of saidring at one side thereof, a generally bar-like member of magnetic material substantially smaller than the space inside the ring located inside the ring and having means defining a second arcuate pole face on one side arranged in opposed relation to the first pole face to define a generally cylindrical region there between, non-magnetic metallic'elements extendingfrom the ends-of said bar-like member to the ring and rigidly connected with both the bar-like member and the ring thereby fixedly and rigidly to support the bar-like member in the ring,'the connection between said elements q and said bar like member and ring comprising notches formed in the ends of said bar-like member and on the inside of said ring, and projections on said elements fitted tightly into said notches, a permanent magnet fitted between the inside of the ring and the other side of the bar-like member, a frame fixed in the said cylindrical region; a core in the frame concentric with said pole faces,.and a coil rotatably mounted in the frame having side portions in' the spaces between the core and the pole faces.

3.. In.an electrical instrument; a ring of magnetic material, means defining a first arcuate pole face on the inside of said ring at one side thereof,a generally barlikemember of magnetic material substantially smaller thanthe spacejinside the ring located inside the ring and having means on one side defining a second arcuate pole .fiace thereon arranged in opposed relation to the firstzpoleface to define a generally cylindrical region there between, a permanent magnet fitted between the inside of the ring and the other side of the bar-like member, non-magnetic metallic elements extending from the ends of said bar-like member to the ring and rigidly connected with both the bar-like member and the ring thereby fixedly and rigidly to support the bar-like member in the ring, the connection between said elements and said bar-like member and ring comprising notches formed in the ends of said bar-like member and inside of said ring, and projections on said elements fitted into said notches, said projections being expanded into tight gripping relation with the walls of said notches, and at least the notches in the ring and the projections fitted therein being dove-tail in configuration, a frame fixed in said cylindrical region, a core in the frame on the axis of said cylindrical region, and a coil rotatable in the frame having side portions in the spaces between said core and said pole faces.

4. In an electrical instrument; a plurality of annular laminations in stacked relation forming a ring of magnetic material, a bar-like member of magnetic material inside each lamination smaller than the space inside the lamination, non-magnetic, metallic elements extending from the ends of each bar-like member to the inside of the pertaining lamination and rigidlyinterlockingly connected with the bar-like member and lamination; one side of each said bar-like member and the inside of the pertaining lamination in opposition thereto having arcuate pole faces defining a cylindrical space, the other side of each bar-like member and the inside of the pertaining lamination opposed thereto being parallel whereby the stacked laminations define a first cylindrical space for receiving a core and moving coil and a second space having parallel walls adapted for receiving a block of permanent magnetic material, there being a block of permanent magnetic material in the last mentioned space tightly engaging the lamination and bar-like member, and extending through substantially the complete thickness of the stacked laminations, means fixedly clamping said laminations together whereby the laminations and the block of permanent magnetic material form an integral unit, a frame of non-magnetic material fixed in said cylindrical space, a magnetic core carried by the frame on the axis of said cylindrical space, and a coil rotatably supported in the frame having side portions in the spaces between said core and pole faces.

5. In an electrical instrument; a plurality of annular laminations in stacked relation forming a ring of magnetic material, a bar-like member of magnetic material inside each ring smaller than the space inside the ring, non-magnetic, metallic elements extending from the ends of each said bar-like member to the inside of the pertaining ring and rigidly connected with the member and ring; one side of said bar-like member and the inside of said ring in opposition thereto having arcuate pole faces defining a cylindrical space, the other side of each member and the inside of the ring opposed thereto being parallel whereby the stacked laminations define a first cylindrical spacefor receiving a core and moving coil and a second space having parallel walls adapted for receiving a block of permanent magnetic material, there being a block of permanent magnetic material in the last mentioned space tightly engaging the ring and member, and extending through substantially the complete thickness of the stacked laminations, there being means fixedly clamping said laminations together whereby the laminations and the block of permanent magnetic material form an integral unit, there being notches extending outwardly from opposite sides of the said cylindrical space between said member and said ring, a core and coil supporting frame of non-magnetic material having side members positioned in said notches, and a core and coil mounted in said frame.

References Cited in the file of this patent UNITED STATES PATENTS 1,964,258 Graham June 26, 1934 2,315,587 Bradshaw Apr. 6, 1943 2,346,521 Triplett Apr. ll, 1944 2,573,183 Chudyk Oct. 30, 1951 2,671,951 Sliwiak Mar. 16, 1954 2,680,285 Furnas June 8, 1954 2,746,142 Maxwell May 22, 1956 2,808,567 Lederer Oct. 1, 1957 FOREIGN PATENTS 358,583 Italy Apr. 22, 1938 

